EEG’s and Seizure Disorders

Question 1

what cell in the brain are responsible for the waves we see in the EEG?

The EEG is the leading test used to help diagnose which condition?

Answer 1

pyramidal cell postsynaptic potentials within the cortex.

seizures

Question 2

The temporal resolution (ms) for which of these EEG is much greater: MRI, EEG, CT?

what is epilepsy?

Answer 2

EEG

recurrent seizures

Question 3

Where do Epileptic Seizures start?

what should we remember about non-epileptic seizures?

Non-epileptic seizures can be divided into what?

Answer 3

the brain

they dont happen by changes in brain electrical activity

Can be divided into Organic NES, and Psychogenic NES.

Question 4

what are these?

1. Ictis (ictal)
2. Postictis (ictal)
3. Interictal
4. Status epilepticus

Answer 4

1. Ictis (ictal):
2. Postictis (ictal): Period immediately following the seizure.
3. Interictal: Period between seizures.
4. Status epilepticus: Continuous seizures or clusters of seizures.

Question 5

what are the types of epileptic seizures?

Answer 5

1. Generalized seizures
2. Generalized tonic clonic
3. Myoclonic
4. Absence
5. Atonic

Question 6

how do we define a generalized seizures?

Answer 6

Affect both hemispheres from the beginning of the seizure.

Loss of consciousness occurs for varying periods of time.

Question 7

how do we define a Generalized tonic clonic?

Answer 7

‘Grand Mal’. Tonic phase includes stiffening of the limbs, clonic phase is jerking of the limbs and face.

Question 8

identify the parts of this EEG during a tonic-clonic seizure

Answer 8

Question 9

how do we define a myoclonic seizure?

hwo do we define an absence seizure?

Answer 9

Rapid, brief contraction of body muscles. Usually involves arms or feet/legs (both sides of body)

Periods of lack of awareness, usually lasting less than a minute.

Question 10

what is another name for absence seizure?

how do we define atonic seizure?

Answer 10

‘Petit Mal

Abrupt loss of muscle tone.

Question 11

what is Myoclonus?

is it normal or abnormal?

Answer 11

Brief, involuntary twitching of a muscle or a group of muscles.

normal

Question 12

what are Types of Epileptic Seizures (Partial)?

how do we differenciate each?

what is a partial seizure?

Answer 12

Simple partial involves no loss of consciousness. Complex partial consciousness is lost or impaired.

partial seizure: area of seizure is limited to one region of the body.

Question 13

what are the Types of Seizures Not Related to Epilepsy (NES)?

Answer 13

1. First Seizures: One time only (induced by drugs, anesthetics, or unknown).
2. Febrile Seizures: Seizures occurring during high fever in children.
3. Dissociative Seizures: Looks like a seizure but no change in EEG. PTSD, panic disorder, are examples, as are factitious (Munchausen’s).
4. Organic causes: Diabetes, syncope, migraine, stroke, tumor, etc.

Question 14

what is Pre-eclampsia?

What is Eclampsia?

Answer 14

• High blood pressure and elevated levels of protein in urine in pregnant women.
• Tonic-clonic seizures (the eclamptic convulsion).

Question 15

what is the Leading cause of maternal and peri-natal death?

Answer 15

Eclampsia

Question 16

what causes seizures?

Answer 16

1. Neurotransmitter imbalance: Low GABA levels in some patients. Some anti-seizures meds are GABAergic.
2. Brain damage/trauma/disease: Irritative lesions can result in seizures.
3. Environmental: Drug use or disuse, lack of sleep, stress, toxins.

Question 17

What are the most frequent point of origin of seizures?

Temporal lobe seizures often preceded by what?

Answer 17

Motor cortex and temporal lobes

auras or hallucinations.

Question 18

what is the Treatment of Seizures?

Answer 18

1. Anticonvulsant meds: Dilantin (phenytoin), Tegretol (carbamazepine); many many more.
2. Surgical removal of focal area (if a focal area can be identified).
3. Diet restrictions (i.e. young children with phenylketonuria). ‘The Ketogenic Diet’
4. Vagus nerve stimulation (VNS): Stimulating

electrode ‘wrapped’ around the left vagus

nerve (less cardiac effects than the right).

Question 19

what is another name for Psychogenic non-epileptic seizures?

how do you treat this type?

Answer 19

dissociative seizures

do not originate from physical causes, thus are treated with therapy and often adjunct meds

Question 20

what structures are involved in sleep?

Answer 20

1. Reticular Formation
2. Serotonin (5-HT)
3. Adenosine
4. Acetylcholine
5. Hypothalamus

Question 21

what does each do?

Answer 21

1. ARAS: Ascending Reticular Activating System (the part of the RF involved in Sleep/Waking).
2. Midbrain ARAS: ‘Drives’ cortex.
3. Pontine ARAS: Turns off midbrain (for sleep).

Question 22

which structure of the reticular formation generates REM sleep (and somaticmuscle inhibition). = Sleep is an active process.?

Answer 22

Pontine ARAS

Question 23

how does the midbrain ARAS get turned off?

how will a Midbrain lesion affect your consciousness?

how will a Pons lesion affect your consciousness?

Answer 23

when 5-HT neurons in pontine RF project to midbrain and get activated

loss of consciousness (can’t ‘drive’ cortex).

constant wakefulness (can’t turn off the midbrain).

Question 24

5-HT depletion will cause?

Answer 24

insomnia

Question 25

when does Adenosine accumulate?

Adenosine A1 receptors are located where?

ACh neurons are involved in what?

Activation of A1 receptors results in what?

Answer 25

during period of high ATP use

in the ARAS.

arousal

inhibit ARAS, resulting in sedation/sleep

Question 26

what part of the hypothalamus gets active during non-REM sleep?

A Bilateral lesion of the anterior nucleus will result in what?

Hypothalamus also involved in what ?

Answer 26

anterior and pre-optic nucleus

insomnia.

Circadian sleep cycle

Question 27

how does the circadian rhythm get set?

Circadian rhythms relating to sleep peak at two time periods, what are these?

Answer 27

Light — Optic nerve — Hypothalamus —

Suprachiasmatic Nucleus — Brainstem.

3am-5am, and 3pm-5pm